Tom Writes: This model is from the 1929 manual in the #9 Mechanical Wonders section. I found this model a test in patience. I would be impressed by the 10 year that can put it together. The order of assembly and orientation of parts is important since many parts are inaccessible once the model is completed. Even orientation of the screw heads vs. nut needs to be considered. I don’t want to admit how much time I spent getting this model working.
It does provide a good example of how rotary motion can be converted to reciprocating with no vertical deflection of the reciprocating linkage (‘straight line’). The biggest challenge is to get the CJ to mesh and track well within the FZ internal gear. I found it necessary to minimize wobble of the CR by wrapping its axle with .001 brass foil where it rotates within the BT. The screw that forms the axle for a CJ must be tightly fastened in one of the CR slots (not a hole). That allows one to adjust the play between the CJ and the FZ. At first I questioned the need for a G 7-hole strip on top of the CJ, as the model would work without it. It turns out that the longer throw of the G strip makes the P57D move with almost no deflection from the horizontal. However, connecting the strip as shown in the manual seems impossible. From the pictures you can get an idea of how I did it. The last thing concerning construction is I do not understand how everything can fit within the dimensions provided by FA screws; I needed to use non-Erector 2 inch screws. It is interesting that the gear ratio between a CJ and an FZ is 1:2 so that the CJ makes exactly 2 revolutions each time it circles within the FZ.